Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G35/00—Reforming naphtha
  • C10G35/04—Catalytic reforming
  • C10G35/06—Catalytic reforming characterised by the catalyst used
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G59/00—Treatment of naphtha by two or more reforming processes only or by at least one reforming process and at least one process which does not substantially change the boiling range of the naphtha
  • C10G59/02—Treatment of naphtha by two or more reforming processes only or by at least one reforming process and at least one process which does not substantially change the boiling range of the naphtha plural serial stages only
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/656—Manganese, technetium or rhenium
  • B01J23/6567—Rhenium
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G35/00—Reforming naphtha
  • C10G35/04—Catalytic reforming
  • C10G35/06—Catalytic reforming characterised by the catalyst used
  • C10G35/085—Catalytic reforming characterised by the catalyst used containing platinum group metals or compounds thereof
  • C10G35/09—Bimetallic catalysts in which at least one of the metals is a platinum group metal
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/36—Accumulators not provided for in groups H01M10/05-H01M10/34
  • H01M10/39—Accumulators not provided for in groups H01M10/05-H01M10/34 working at high temperature
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to catalytic reforming using platinum-rhenium catalysts with relatively high rhenium content.
• Catalytic reforming to upgrade naphtha or low-boiling range hydrocarbons to higher octane gasoline has been practiced for many years using catalysts compris ⁇ ing platinum on a refractory support, such as alumina.
• a catalyst comprising platinum and rhenium on alumina provided greatly improved yield stability and a much lower fouling rate. See U.S. Patent No. 3,415,737 to Kluksdahl.
• references referred to above are not directed to the use of catalytic reforming catalysts con ⁇ taining rhenium in excess of a base ratio of rhenium to platinum. Also, the references do not direct toward the use of high rhenium to platinum ratio catalyst in the first stage (although the language may admit of such use in some instances) and instead, the references tend to direct away from the use of high rhenium to platinum ratio catalyst in the first stages. See, for example, the Mooi reference which states at Column 2, line 38, "It has been found that the presence of rhenium tends to inhibit and have a dele ⁇ terious affect upon the activity of the platinum group metal catalyst to catalyze a naphthene dehydrogenation reaction.”
• Naphthene dehydrogenation is one of the main reactions taking place in the first stage of a multi-stage catalytic reforming unit. Also, it may be noted that typically in the above references, the ratios of rhenium to platinum preferred for the first stage catalysts are 1.2, 1.0, or lower ratios.
• a process for catalytic reforming.
• the process comprises
• a last stage catalyst comprising rhenium and 0.2 to 2.0 weight percent platinum, and having sufficient rhenium so that the last stage catalyst has at least 0.5 weight percent rhenium beyond that necessary to attain a 1.7 rhenium to platinum weight ratio.
• the ratio of rhenium to platinum is at least 1.8 for the first stage catalyst, and the last stage catalyst contains sufficient rhenium so that it has at least 0.5 weight percent rhenium beyond that necessary to attain a 1.8 ratio.
• Particularly preferred catalysts for use in the process of the present invention are those wherein the ratio of rhenium to platinum for the first stage catalyst is at least 2.0, and wherein the last stage catalyst contains sufficient rhenium so that it has at least 0.5 weight percent rhenium beyond that necessary to attain a ratio of 2.0 rhenium to platinum. 5
• the ratio of rhenium to platinum in the first stage catalyst is from 1.7 to 5.0
• the rhenium is from 0.35 to 3.0 weight percent of the catalyst and the platinum is from 0.2 to 1.7
• ⁇ ° catalyst is from 3.0 to 10.0, the rhenium is from 0.7 to 6.0 weight percent of the catalyst and the platinum is from 0.2 to 2.0.
• the rhenium is from .35 to 3.0 weight percent of the catalyst and the platinum is from .2 to 1.7 weight percent, and wherein the ratio of rhenium to platinum in the last stage catalyst is from 3.0 to 7.0, the rhenium is from .9 to 6.0 weight percent of the
• ⁇ ° catalyst and the platinum is from .2 to 2.0 weight percent of the catalyst.
• the amount of rhenium in the last stage catalyst is at least 0.5 weight percent greater
• the present invention is based on our finding that advantageous results in terms of run length and maintenance of product yield are achieved
• the last stage preferably has a 3.0 or higher ratio of rhenium to platinum by weight for the catalyst. More preferably, the ratio of rhenium to platinum for the last stage is 4.0 or higher and still more preferably, 5.0 or higher.
• the present process requires the ratio of rhenium to platinum be considerably greater than 1 or 1.2 in the catalysts of the forward stages.
• the ratio of rhenium to platinum for the catalyst is at least 1.7, preferably at least 1.8 and most preferably about 2.0 or higher.
• Particularly preferred ratios for rhenium to platinum for the catalyst in the first stage or forward stages are within the range of about 1.7:1 to 3.0:1.
• More than one catalyst can be used in the forward stages (stages ahead of the last stage), but in the present invention these catalyts all must have relatively high rhenium to platinum ratios, preferably ratios of at least 1.7.
• first catalyst the catalyst in the first stage, (or the forward stages, if all contain the same catalyst) is herein referred to simply as "first catalyst".
• FIG. 1 is a schematic illustration of a multi ⁇ stage catalytic reforming process.
• FIG. 2 illustrates the results of two reforming runs, one in accordance with the present invention and one not.
• fresh feed is introduced to the catalytic reforming unit or process via line 1.
• Fresh feed to the reforming process is a light hydrocarbon feed, for example, a naphtha frac ⁇ tion.
• the naphtha will boil in a range falling within the limits of from about 150 to 450°F and prefer ⁇ ably from about 190 to 400°F.
• the hydrocarbon feedstock can be, for example, either a straight run naphtha or a thermally cracked or catalytically cracked naphtha or blends thereof.
• the feed to the reformer be substantially sulfur free; that is, the feed preferably contains less than about 5 pp sulfur, and more preferably less than 1 ppm, and still more preferably, less than .3 ppm.
• acceptable levels can be reached by hydrotreating the feedstock in a pretreatment zone where the naphtha is contacted with a hydrogenation catalyst which is resistant to sulfur poisoning.
• a suitable catalyst for this hydrode- sulfurization process is, for example, an alumina-contain ⁇ ing support upon which is dispersed a minor proportions of molybdenum and cobalt.
• Hydrodesulfurization is ordinarily conducted at a temperature from 550°F to 800°F, a pressure from 200 to 2000 psig, and a liquid hourly space velocity from 1 to 5.
• the sulfur contained in the naphtha is generally converted to hydrogen sulfide which can be removed as a gas prior to the reforming reactors using suitable conventional means.
• Recycle hydrogen is combined with the light hydrocarbon feed via line 2, heated in exchanger 3 and in furnace 4, and then the combined hydrogen and naphtha ' feed are introduced to the first stage catalytic reforming reactor 6.
• the feed is contacted with a first catalyst comprising platinum and rhenium on an inorganic refractory support, such as an alumina support.
• the first catalyst has a high rhenium to platinum ratio, preferably at least 1.7, more preferably at least 1.8, most preferably at least 2.0.
• the primary reaction in the first stage is generally dehydrogenation. However, other reactions occur and the first stage reactor is part of an integrated series of reactors for achieving the overall catalytic reforming to upgrade the hydrocarbon feed to high octane product.
• the platinum rhenium catalyst used in the first stage reactor 6, as stated above, is supported on a refractory oxide, such as alumina. Also, it is preferred to include a halide in the catalyst, especially chloride. Preferred amounts of the halide, such as chloride, are from .5 to 1.5 weight percent of the catalyst.
• the effluent from the first stage reforming reactor is withdrawn via line 7, heated in furnace 8 and introduced via line 9 to the second stage reforming reactor, reactor 10.
• the effluent of reactor 10 is withdrawn via line 11, heated in furnace 12 and then fed via line 13 to reactor 14. Additional dehydrogenation occurs in the second and third stage reactors, and also dehydroisomeriza- tion, and dehydrocyclization.
• the catalysts used in these intermediate stages also have high rhenium to platinum ratios, as is the case with the catalyst used in the first stage.
• different catalysts can be used in each of the forward stages, that is, reactor 6 as stage 1, reactor 10 as stage 2 and reactor 14 as stage 3, according to one preferred embodiment, the same high rhenium catalyst is used in all of these forward stages.
• the rhenium to platinum ratio is at least 1.7 for the catalyst used in all of these forward stages.
• the amount of catalyst used in the forward stages may be from 10 to 70 volume percent of the total catalyst used in the reforming unit, preferably from 30 to 50 volume percent.
• the stage containing the largest single amount of catalyst is the last stage, which is reactor 18 in FIG. 1.
• the number of stages prior to the last stage can be more or less than the three reactor stages shown in the schematic drawing. A minimum of one stage is used prior to the last stage and at least two different catalysts are used in the process.
• the effluent from reactor 14 is passed via line 15 to furnace 16 and then introduced via line 17 to the last stage of reactor 18.
• the effluent from reactor 18 is withdrawn via line 19, cooled in heat exchanger 20 and then hydrogen-rich recycle gas is separated as schematically indicated in separator 21.
• the hydrogen-rich gas is compressed via compressor 23 and recycled via line 2. Excess net hydrogen is withdrawn via line 24.
• Product reformate is withdrawn from separator 21 via line 25. This product material is passed to a dis- tillation section to remove light ends, etc., and obtain product Cr+ reformate.
• the catalyst used in the last stage has rhenium in excess of that needed to achieve a 1.7 ratio of rhenium to platinum.
• the excess rhenium is at least 0.5 weight percent based on the weight of the catalyst, more preferably .5 to 1.5 weight percent, in excess of the rhenium required to attain a 1.7 ratio of rhenium to platinum.
• the present description is simplified to a first catalyst used in one or more of the reaction zones ahead of the last reaction zone, and a last stage catalyst which is used in the last reaction zone or last reactor of the reforming unit.
• the last stage catalyst is preferably 30 to 90 volume percent of the total catalyst in the reforming unit, more preferably, 50 to 70% of the total catalyst volume in the reforming unit.
• One of the primary reactions in the last stage is dehydrocyclization.
• the catalyst used in the last stage for dehydrocyclization and other reforming reactions is supported on a refractory inorganic oxide support, preferably alumina, and also preferably contains a halide, as is the case with the catalysts used in the forward stages of the reforming unit.
• the amount of catalyst used in the various stages is preferably sufficient so that the overall liquid hourly space velocity (LHSV) is from .5 to 4.0, more preferably from .8 to 2.5.
• the hydrogen recycle gas rate in terms of recycle moles of hydrogen per mole of hydrocarbon fresh feed is from 2.0 to 15, more preferably from 3.0 to 10.0.
• Preferred total pressures are from 100 to 350 psig in the various stages of the reforming unit.
• Preferred catalyst average temperatures are from 800 to 1000°F. The temperature varies from inlet to outlet of the reactors as most of the reforming reactions are endothermic. Inlet temperatures may be from 850 to 1000°F and outlet temperatures may be from 750 to 1000°F. Also, the temperature varies during the course of the run, with average start-of-run temperatures for typical semi-regenerative operation being at the lower end of the 800 to 1000°F range and end-of-run temperatures being at the upper end.
• the present invention is preferably applied to semi-regenerative reforming operations, with onstream run lengths of 500 to 8000 hours, preferably 1000 to 5000 hours CATALYSTS
• the catalysts which find use in the reforming process of the present invention comprise a halided, porous " inorganic oxide carrier or support containing from 0.2 to 2 weight percent platinum promoted with 0.35 to 6.0 weight percent rhenium.
• porous inorganic oxide support is meant an inorganic oxide having a surface area preferably from 50 to 700 m 2 /gm and more preferably from 150 to 400 m 2 /gm.
• the support can be a naturally occurring or syn ⁇ thetically produced inorganic oxide or combinations of inorganic oxides.
• Acidic inorganic oxide supports can be used, such as the naturally occurring aluminosilicates, particularly when acid treated to increase the activity, or synthetically produced cracking supports, such as silica- alumina, silica-zirconia, silica-alumina-zirconia, silica- magnesia, silica-alumina-magnesia, and crystalline zeolitic aluminosilicates.
• cracking supports such as silica- alumina, silica-zirconia, silica-alumina-zirconia, silica- magnesia, silica-alumina-magnesia, and crystalline zeolitic aluminosilicates.
• reforming processes are preferably conducted in the presence of catalysts having a low cracking activity, i.e., catalysts of limited acidity.
• preferred catalyst supports are inorganic oxides such as magnesia and alumina.
• the catalytic carrier or support which is parti- cularly preferred for purposes of this invention is alumina. Any of the forms of alumina meeting the above- stated surface area specifications can be used, although gamma alumina is especially preferred. Furthermore, alumina can be prepared by a variety of methods satisfactory for purposes of this invention. The preparation of alumina for use in reforming catalysts is well known in the art.
• the platinum and rhenium are disposed in intimate admixture with each other on the porous inorganic oxide catalyst support.
• the platinum and rhenium can be disposed by suitable techniques such as i.on-exchange, copreci•pi•ta- tion, impregnation, etc.
• One of the metals can be associated with the carrier by one procedure, for example ion-exchange, and the other metal associated with the carrier by another procedure, e.g., impregnation.
• the metals are usually associated with the porous inorganic oxide support by impregnation.
• the catalyst can be prepared either by coi pregnation of the metals onto the porous inorganic oxide carrier or by sequential impregnation.
• the carrier material is impregnated with an aqueous solution of a decomposable compound of the metal in sufficient concentration to provide the desired quantity of metal in the finished catalyst and the resulting mixture is then heated to remove volatiles.
• Chloroplatinic acid is an example of an acceptable source of platinum.
• platinum-containing compounds e.g., ammonium chloro- platinates and polyamrnineplatinum salts, can also be used.
• Rhenium compounds suitable for incorporation onto the carrier include, among others perrhenic acid and ammonium perrhenates.
• Incorporation of the metals with the carrier can be accomplished at various stages of the catalyst prepara ⁇ tion.
• the incor ⁇ poration may take place while the alumina is in the sol or gel form followed by precipitation of the alumina.
• a previously prepared alumina carrier can be impregnated with a water solution of the metal compounds.
• the reforming activity of the catalyst is promoted by the addition of halides, particularly fluoride or chloride.
• the halides provide a limited amount of acidity to the catalyst which is beneficial to most reforming operations.
• the catalyst promoted with halide preferably contains from 0.1 to 3 weight percent total halide content and more preferably from 0.1 to 2 weight percent and still more preferably from 0.5 to 1.5 weight percent.
• the halides can be incorporated onto the catalyst carrier at any suitable stage of catalyst manufacture, e.g., prior to or following incorporation of the platinum and rhenium. Some halide is often incorporated onto the carrier when impregnating with the metals; e.g., impregnation with chloroplatinic acid results in chloride addition to the carrier.
• halides can be incorporated onto the support simultaneously with incorporation of the metal(s) if so desired.
• halides are combined with the catalyst carrier by contacting suitable compounds such as hydrogen fluoride, ammonium fluoride, hydrogen chloride, or ammonium chloride, either in the gaseous form or in a water soluble form with the carrier.
• suitable compounds such as hydrogen fluoride, ammonium fluoride, hydrogen chloride, or ammonium chloride, either in the gaseous form or in a water soluble form with the carrier.
• the fluoride or chloride is incorporated onto the carrier from an aqueous solution containing the halide.
• the resulting composite is usually dried by heating at an elevated temperature usually no greater than about 500°F and preferably at about 200°F to 400°F. Thereafter the composite is usually calcined at an even higher temperature, e.g., from 900°F up to about 1050°F.
• the carrier containing platinum and rhenium is heated at an elevated temperature in a reducing atmosphere to convert the platinum to the metallic state and reduce the valence state of the rhenium.
• the heating is performed in the presence of hydrogen, and more preferably in the presence of dry hydrogen.
• this reduction be accomplished at a temperature in the range of 500°F to 1000°F, and preferably 500°F to 800°F.
• the catalyst composite used in the present invention i.e., platinum and rhenium supported on a porous inorganic oxide carrier, should be sulfided for use in the naphtha reforming process.
• Presulfiding can be done in situ or ex situ by passing a sulfur-containing gas, e.g., H2S, through the catalyst bed.
• a sulfur-containing gas e.g., H2S
• Other presulfiding techniques are known in the prior art.
• the catalyst can be sulfided on startup by adding a sulfur-containing compound, e.g. , H
• reaction zone 05 introduced to the reaction zone in any convenient manner. It can be contained in the liquid hydrocarbon feed, the hydrogen rich gas, a recycle liquid stream or a recycle gas stream or any combination thereof. After operating the reforming process in the presence of sulfur for a period of
• the addition of sulfur is preferably discontinued.
• the purpose for presulfiding the catalyst prior to contact with the naphtha or sulfiding the catalyst during the initial contact with naphtha is to * ⁇ ⁇ * reduce excessive hydrocracking activity of the catalyst which results in the production of high yields of light hydrocarbon gases, for example, methane.
• Tests were made in laboratory reforming units 0 having two reactors in series to compare a single high rhenium catalyst system (Run A) with a catalyst system having high rhenium catalyst in the first stage and very high rhenium catalyst in the last stage (Run B).
• a 2:1 rhenium to platinum 5 catalyst (comprising 50% of the total catalyst volume) was loaded in three layers separated by alundum interlayers to simulate the temperature profiles in the first three reactors of a four reactor reformer.
• the second reactor contained a single catalyst layer and represented a final 0 reforming stage containing 50% of the total catalyst volume for the reforming unit.
• the second reactor vessel contained the same 2:1 rhenium to platinum catalyst as in the first reactor.
• the catalyst in the second reactor contained 0.9 weight percent rhenium in excess of 5 the amount needed to attain the 2:1 rhenium to platinum ratio of the first stage catalyst.
• both catalysts contained chloride in the range of .6 to 1.0 weight percent and the support was alumina.
• the average temperature of the second reactor was 0 maintained 30°F higher than that of the first reactor to simulate the temperature profile typical in a commercial reforming unit run with equal inlet temperatures.
• the feed for both Run A and Run B was a Heavy Arabian Naphtha having an API gravity of 57.2; mass spec analysis of 65.6% paraffins, 21.1% naphthenesr and 13.1% aromatics; and D-86 distillation of start to 5LV%, 218/236°F; 10 to 20LV%, 243/250°F; 30 to 40LV%, 259/268°F; 50LV%, 277°F; 60/70LV%, 288/300°F; 80/90LV%, 314/330°F; 95LV%/EP, 344/387°F.
• Reaction conditions were 200 psig, 2.8 liquid hourly space velocity (LHSV), 3.5 hydrogen to fresh feed hydrocarbon ol ratio, and constant product octane of 98.5 RON.
• FIG. 2 compares the run plots of the single catalyst system (Run A) and the dual catalyst system (Run B).
• the dual catalyst system had a cycle length 40% longer than, and the same C 5 + liquid yield as, the single catalyst system. In each case, end of run was taken as the point at which C ⁇ + liquid yield had dropped by 1LV% from its maximum value.
• the time-temperature curves in FIG. 2 represent the weighted average temperature of two reactors in each run normalized to the target octane.

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